A simple Scala example of implicit classes:
implicit class EnhancedString(str:String) {
def prefix(prefix:String)= prefix+ str
}
println("World".prefix("Hello "))
As Tarun said, you have to import it if it's not in the same class where
you use it.
Hope this makes it clearer,
Michal Senkyr
On 5.12.2016 07:43, Tarun Kumar wrote:
Not sure if that's documented in terms of Spark but this is a fairly
common pattern in scala known as "pimp my library" pattern, you can
easily find many generic example of using this pattern. If you want I
can quickly cook up a short conplete example with rdd(although there
is nothing really more to my example in earlier mail) ? Thanks Tarun Kumar
On Mon, 5 Dec 2016 at 7:15 AM, long <longteng...@gmail.com
<mailto:longteng...@gmail.com>> wrote:
So is there documentation of this I can refer to?
On Dec 5, 2016, at 1:07 AM, Tarun Kumar [via Apache Spark
Developers List] <[hidden email]
<http:///user/SendEmail.jtp?type=node&node=20104&i=0>> wrote:
Hi Tenglong, In addition to trsell's reply, you can add any
method to an rdd without making changes to spark code. This can
be achieved by using implicit class in your own client code:
implicit class extendRDD[T](rdd: RDD[T]){ def foo() } Then you
basically nees to import this implicit class in scope where you
want to use the new foo method. Thanks Tarun Kumar
On Mon, 5 Dec 2016 at 6:59 AM, <<a
href="x-msg://19/user/SendEmail.jtp?type=node&node=20102&i=0"
target="_top" rel="nofollow" link="external" class="">[hidden
email]> wrote:
How does your application fetch the spark dependency? Perhaps
list your project dependencies and check it's using your dev
build.
On Mon, 5 Dec 2016, 08:47 tenglong, <<a
href="x-msg://19/user/SendEmail.jtp?type=node&node=20102&i=1"
target="_top" rel="nofollow" link="external" class="">[hidden
email]> wrote:
Hi,
Apparently, I've already tried adding a new method to RDD,
for example,
class RDD {
def foo() // this is the one I added
def map()
def collect()
}
I can build Spark successfully, but I can't compile my
application code
which calls rdd.foo(), and the error message says
value foo is not a member of org.apache.spark.rdd.RDD[String]
So I am wondering if there is any mechanism prevents me
from doing this or
something I'm doing wrong?
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